[all variants] How can I boot from a USB on a UEFI system with only Ubuntu installed?

Thread moved to General Help.

Welcome. Seems your issue is you can't access your BIOS. You gotta be quick! At least I do. I start pressing immediately at the manufacturer splash screen, or even before!

On that split second screen it should show you the key to press to get to BIOS, if you don't already know it. Could be del, F2, ESC. Try them, check the manual.

Any luck? UEFI makes no difference here, goes to BIOS or Boot Device menu when I hit the correct key at boot.

PS: Win10 would have been in UEFI so you have tried the same procedure you did last time I suppose?